Field of the Invention
The invention is related to an optical device and a projector, and particularly related to a wavelength conversion device and a projector having the wavelength conversion device.
Description of Related Art
Recently, projection apparatus applying a solid state light source such as light-emitting diodes (LEDs) and laser diodes gradually becomes popular in the market. Since a lighting efficiency of the laser diode is about 20% higher than a lighting efficiency of the LED, in order to break through the light source limitation of the LED, a technique of using the laser light source to excite the phosphor powder to generate a pure color light source required by the projector is gradually developed. Moreover, the laser projection apparatus can use the laser beam provided by the laser diode to excite the phosphor powder to emit light as the illumination light source for the projector, so as to meet different brightness requirements of the projector. Therefore, the laser light source device serving as a light source system of the projector has a great potential to replace conventional high pressure mercury lamps to become the light source of the projectors of a new generation.
For current laser projectors, generally a phosphor powder adhesive layer is coated on a metal substrate with high reflectivity to constitute a phosphor wheel, and the laser beam (e.g. blue light) emitted by the laser light source device excites the phosphor powder adhesive layer on the metal substrate of the phosphor wheel so as to generate light beam with different colors (such as green light and yellow light); and the laser beam can directly pass through the phosphor wheel by going through a slot on the metal substrate or via a transparent plate disposed on the metal substrate, in order to generate light with multiple colors. Specifically, if the phosphor powder adhesive layer is directly coated on the metal substrate, the adhesion between the phosphor powder adhesive layer and the metal substrate may not be good due to high concentration of the phosphor powder in the phosphor powder adhesive layer, causing the phosphor powder adhesive layer to fall off the metal substrate of the phosphor wheel easily. On the other hand, if a modifier is used as the adhesive medium for adhering the phosphor powder adhesive layer with the metal substrate to solve the poor adhesion issue, the reflectivity of the metal substrate may be reduced due to the chemical reaction generated between the modifier and the metal substrate, and consequently the optical quality of the laser projector may be lowered as well.
The information disclosed in this BACKGROUND section is only for enhancement of understanding of the BACKGROUND section of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the BACKGROUND section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.